Heat indicator



L. BODDY HEAT INDICATOR I June 11, 1935.

Filed July 6, 1931 INVENTOR Zeonari 50a"? ATTO RNEYS Patented June 1 1, 1935 UNITED STATES PATENT OFFICE HEAT INDICATOR Leonard Boddy, Ann Arbor, Mich., assignor to g-Seeley Corporation, Ann Arbor, Mich., a corporation of Michigan Application July 6, 1931, Serial No. 549,074 4 Claims. (01. 73-52) The invention relates to indicating devices and water jacket of the engine. The glass tube is refers more particularly to devices having a movfrictionally secured to the support by the resilient able column of indicating liquid within a transbifurcated clamp l2 secured to the back of th parent tube. One of the objects is to so consupport and having its bifurcations or fingers struct the device that it indicates at a point reembracing and resiliently engaging the glass tube 5 mote from that causing movement of the indinear its upper end. cating llqllld. Another object is to so construct The tube 3 comprises the capillary tube secthedevlce that it is accurate in operation and tions l3 and I4 formed of suitable metal, such Its indicat ng liquid is effectively retained. A as copper, and the adapter section l5 formed further ob ect is to so construct the tube for of suitable metal, such as brass, and connecting 10 Placing the bulb and the transparent tube of the the adjacent end portions of the tube sections device in communication that the communicatl3 and I4. The adapter section has the axially mg and transparent tubes are directly hermetialigned recesses or bores I6 and I! and the intercally sealed to each other. These and other obmediate axially aligned capillary passageway l8 l6 ects of the invention will become apparent from and the tube sections l3 and I4 have adjacent end the following description, taken in connection portions resp ctiv ly en a in the recesses with the accompanying drawing, in which bores I6 and I! and abutting the shoulders .Figure 1 is a side elevation, partly in section, formed at their inner ends, by means of which the showing a heat indicator embodying my inventube sections are properly located in the adapter $1011} section and pockets within thevadapter section 20 F gure 2 is a front elevation thereof; for collecting air are eliminated. These tube see- Figure 3 is an enlarged sectional detail view tions are suitably secured to the adapter section of the bulb of the heat indicator; as by solder. The adapter section I5 is mounted Figure 4 is an enlarged sectional detail view upon and secured to the back, of the support Ill of the adapter; r and the tube section I 3 is preferably formed with 25 F1gure'5 is a view similar to'Figure 1, showing the vertically extending U-portion below the a modified construction. I glass tube. This tube section, being pliable, may My Invention, as illustrated in the present inbe readily bent to raise .or lower. the glass tube, stance, is embodied in a heat indicator which is with respect to the graduations lI. The other specifically shown as applied to an internalcomend portion of the tube section l4 extends into 30 bustion engine of a motor vehicle. In detail, the the recess or bore 19 in the cap and abuts an heat indicator has the bulb I, the transparent annular shoulder formed at the inner end of tube 2 and the tube 3 between the bulb and the the recess or bor velirlflinetting a y pocket in th I transparent. tube for placing the same in comcap for trapping air. This end portion is suit- 5 munication. 1 v ably secured to thecap as by solder. The bulb I may be suitably secured to the en-I The tube' section. I 3 has thevertically extendgine in either a horizontal or vertical position to me end portion 20 whi is hermetically sealed extend within its water jacket and this bulb directly within the lowe e d portion of the glass comprises the hollow body 4 formed of suitable tube 2. This is accomplished by holding the end 0 metal, such as brass. The body has the closed p rtion 20 andthe'lower nd portion of he glass 40 end 5 and the cap 6 also formed of suitable metal, tube 2 adjacent to each other and subjecting the such as brass, and permanently secured to the same to a proper flame to oxidize the end poropen end of the body. The cap 6 preferably has tion 20 and reduce the inner diameter of the the bevelled annular shoulder I for engaging the lower end portion of the glass tube, so that the bevelled annular shoulder 8 formed in theopenlatter encircles and fuses upon and is Welded ing of the outer wall of the engine and the shoulto the former when properly oxidized. To take der I is clamped against the shoulder 8 by suitcare of the cooling of the tube section l3 and able means, such as the nut 9 threaded into the glass tube 2 after they have been fused and weldouter wall and abutting the cap 6, thereby seed together without destroying the seal or breakcuring the bulb in place. ing the glass tube, the tube section I3 is formed The transparent tube 2 is a glass tube and is with a. relatively thin wall as compared to that vertically mounted in the metal support or head of the tube section I4 with the result that while III, which carries the graduations II at one side the external diameters of these tube sections of the glass tube for indicating the degree of are substantially the same, the internal diameters heat or temperature of the cooling medium in the appreciably differ with the internal diameter of the tube section l3 the larger. The thickness of the wall of this tube section l3 as compared to its diameter is such that the material forming the tube section will yield during the cooling to remain with the glass.

For supporting and protecting the tube section I, I have provided the pliable coil 2| encircling this tube section and encircling and mounted at its ends upon the nipple 22 of the cap 6 andthe nipple 23 of the adapter section IS.

The cap 6 has an opening therethrough for placing the. tube section in communication with the interior of the hollow body 4 and this opening comprises the capillary passageway 24 at the end of the tube section l4 and the outwardly flared passageway 25 extending from the capillary passageway to the inner end of the cap. By reason of this construction trapping oi: air within the bulb is avoided in the operation of the heat indicator, so that the correct temperature will be indicated.

To eifectively secure the cap 6 to the body 4 and also to avoid the entrance of material into the body which might enter and clog the capillary passageway in the cap, I have provided the inner end portion of the cap with the external annular flange 26 and the external annular groove 21 with the flange innermost and of a diameter slightly greater than the internal diameter of the body and having a force fit with the body. The end of the body is formed with one or more notches 28 through which solder may pass into the groove, the flange preventing the solder from entering the body.

The indicating liquid fills the bulb l and the tube 3 and extends upwardly within the glass tube 2 to a predetermined height within this tube at a predetermined temperature and in order to take care of the different commercial internal diameters of the glass tube the body 4 of the bulb preferably has its open end portion cut off at different distances dependent upon the internal diameter of the glass tube to secure a predetermined ratio of volume of the body of the bulb to volume of the glass tube for a predetermined length. Another method of securing this result, as shown in Figure 5, is to insert within the bulb one or more displacement members having a predetermined volume and a coefficient of expansion less, and preferably considerably less,

than that of the indicating liquid.

The upper end of the glass tube is hermetically sealed so that the portion of the glasstube abovethe indicating liquid is filled with air which, upon expansion of the indicating liquid by reason of subjecting the bulb to an increased temperature, creates a pressure upon the indicating liquid to assist in returning the same to normal position upon cooling of the bulb. Furthermore, by reason of the hermetically sealed upper end of the glass tube, loss of the indicating liquid by evaporation is prevented and the boil ing point of the indicating liquid is raised and also entrance of impurities, such as moisture, dirt, etc. into the indicating liquid is prevented, thereby avoiding rendering the heat indicator inaccurate or inoperative.

What I claim as my inventionis:

1. In an indicating device, the combination with a glass tube, of a metal tube member having an end portion extending within and hermetically sealed directly to said glass tube by fusing and welding, said tube member having such wall thickness that the material forming the tube will yield to avoid breaking the seal upo'n contraction of the glass tube during cool ing, and said glass tube and metal tube member adapted to contain an indicating liquid.

2. In an indicating device, the combination with a glass tube, of a metal tube connected to said glass tube and comprising a metal tube section having an end portion extending within and hermetically sealed directly to said glass tube by fusing and welding, the end portion of said tube section having such wall thickness that V the material forming the same will yield to avoid breaking the seal upon contraction of the glass tube during cooling, a second metal tube section, and means connected to adjacent ends of said metal tube sections having a passageway therethrough in communication with said metal tube sections.

3. In an indicating device, the combination with a glass tube, of a tube member having a yieldable end portion extending a substantial distance within and having an extended contact with said glass tube, said end portion being hermetically sealed directly to said glass tube by fusing and welding, said end portion also being sufficiently yieldable to avoid breaking the seal upon contraction of the glass tube during cooling and said glass tube and tube member adapted to contain an indicating liquid.

4. In an indicating device, the combination with a glass tube, of a metal tube connected to ,said glass tube and comprising a metal tube section having an end portion extending within and hermetically sealed directly to said glass tube by fusing and welding, said tube section having such wall thickness that the material forming the tube sectionwill yield to provide for limited adjustment of the glass tube, a second metal tube section, and an adapter connecting the adjacent ends of said metal tube section and having a passageway therethrough in communication with the latter sections.

LEONARD BODDY. 

